It would be nice if you could go snoop around the house, I doubt that the notes is all there is, I even doubt that Stacy was the one to leave them.Maybe organize a possible break in, at night? Of course two minuses:1. You can get caught.2. It's at night.
I can't believe Stacy's dead, and she died not long after you from what her grandmother said. There has to be a clue in those notes.